Which hot water system is best: gas, electric, solar or heat pump?
Gas hot water system
Until recently, high-efficiency natural gas hot water systems were considered the most economical type of water heater. Heat pump hot water systems, which run on electricity, are now much more efficient.
Gas-powered hot water systems should generally be reserved for instantaneous systems. That’s because storage systems use a burning gas flame to heat the water in the tank, and fire safety requires that there be no insulation at the bottom of the tank. This lack of insulation means that gas storage systems will experience higher heat loss compared to other hot water systems.
Gas hot water systems have a medium to high purchase, installation and running cost.
Electric hot water system
Resistive element electric hot water systems are currently used by about 50 per cent of Australian households, according to the DCCEEW. That may be because they are the cheapest hot water system to purchase and install. But unless they are powered by a solar PV system, electric hot water systems are the most expensive to run.
Solar hot water system
Solar hot water systems use energy from solar panels or collectors to heat water that flows into an insulated storage tank placed on the roof or the ground. Cold areas or winter months may require solar hot water tanks to use a booster powered by gas or electricity to help heat the water. While they are generally expensive to purchase and install, Sustainability Victoria reports that they use at least 60 per cent less energy than a conventional gas or electric hot water system.
Heat pump hot water system
Heat pump hot water systems are highly efficient, with almost an 80 per cent increase in efficiency compared to a resistive element electric hot water system. That’s because heat pump systems extract heat from the air to warm your water, rather than generating heat directly. In cold locations where temperatures regularly drop below 5°C, you will need a special heat pump water heater that is designed to work in frosty, snowy conditions.
Heat pump hot water systems can cost more upfront to purchase and install, but there are rebates available and they can cut down energy bills over the long run. If you have solar panels installed on your home, a heat pump system can also function like a battery, using your solar power to heat the water when the sun is shining and storing it for use when you need it later on, reducing your bills even further.
Heat pumps have very little risk of overheating in hot weather, since its compressor switches off once the stored water reaches the right temperature. Since a fan is needed to pull outside air into the heat pump’s evaporator, they can produce some noise, but quality heat pump hot water systems like the Apricus and Reclaim heat pumps are very quiet.